Syntheses and characterization of polymer conjugates of 9-[2-(phosphonomethoxy)ethyl] (PME) derivatives of adenine (PMEA), 2,6-diaminopurine (PMEDAP) and guanine (PMEG) are described. The phosphonate group of these acyclic nucleotide analogues was activated by reaction with triphenylphosphine and di(2-pyridyl) disulfide (TPP-PDS). The activated phosphonate reacted with a random copolymer containing N-(2-hydroxypropyl)methacrylamide (HPMA) and N-(3-methacrylamidopropanoyl)ethane-1,2-diamine (Ma-AP-ED) units. The phosphonamide bond between the nucleotide and polymer carrier proved to be relatively stable at physiological pH 7.4 while at pH 5.0 (corresponding to endosomal or lysosomal compartments of cells) underwent slow hydrolysis. The rate of hydrolysis (drug release) was shown to depend on the detailed structure of the heterocyclic base. The polymer-drug conjugates described in the paper represent a new family of antiviral and cytostatic drugs with potentially improved pharmacokinetics, sustained drug release and diminished non-specific toxicity.
描述了腺嘌呤(PMEA)的9-[2-(磷酸甲氧基)乙基](PME)、2,6-二氨基嘌呤(PMEDAP)和鸟嘌呤(PMEG)的聚合物共轭物的合成和表征。这些开链核苷类似物的磷酸酯基通过与三苯基膦和二(2-吡啶基)二硫化物(TPP-PDS)反应而被激活。激活的磷酸酯基与含有N-(2-羟基丙基)甲基丙烯酰胺(HPMA)和N-(3-甲基丙烯酰胺基)乙烷-1,2-二胺(Ma-AP-ED)单元的随机共聚物发生反应。核苷和聚合物载体之间的磷酰胺键在生理pH 7.4下被证明相对稳定,而在pH 5.0(对应于细胞内的内体或溶酶体区)时发生缓慢水解。水解速率(药物释放)被证明取决于杂环碱基的详细结构。文章中描述的聚合物-药物共轭物代表了一类新的抗病毒和抗细胞增生药物,具有潜在改进的药代动力学、持续的药物释放和降低的非特异性毒性。